Method and apparatus for reducing tension and traversing glass fiber strand

ABSTRACT

A method and apparatus for reducing the tension of continuous glass fiber strand is disclosed. The apparatus is composed of a traveling surface rotating about an axis. The surface has a plurality of tracks of variable lengths running oblique to the axis of rotation of the surface. The termination point of the track on the traveling surface is also the point of origin of a subsequent track, thus a continuous irregular path is defined by the tracks. The tracks are determined by a plurality of contact points on which the glass fiber strand engages. The surface travels at a slightly greater linear speed than the take-up winder thus reducing the tension of the strand on the glass fiber strand package. Additionally, the surface may be reciprocally traversed the length of the take-up package or alternatively the take-up package can be traversed to obtain a random wind of glass fiber strand.

' United States Patent 1 Drummond [451 Apr. 8, 1975 [75] Inventor:Warren W. Drummond, Allison Park, Pa.

7 [73] Assignee: PPG Industries, Inc. Pittsburgh, Pa..

[22] Filed: Mar. 27, 1974 21 Appl. No.: 455.470

[52] US. Cl 65/2; 65/3; 65/11 W; 242/18 G; 242/432 [51] Int. Cl C03b37/02 [58] Field of Search 65/2. 3. 11 W; 242/18 G. 242/43. 155 R. 43.2;28/1.8, 72.15

[56] References Cited UNITED STATES PATENTS 2.786.637 3/1957 Russell eta1 65/11 W 2.802.366 8/1957 Borner 242/155 R 3.279.904 10/1966 Russellet a1 65/11 W 3.293.013 12/1966 Drummond 65/11 W FOREIGN PATENTS ORAPPLlCATlONS 1.242.197 4/1960 France 65/11 W Primary ExuminerRobert L.Lindsay, Jr. Attorney. Agent. or F irmRobert De Majistre [57] ABSTRACT Amethod and apparatus for reducing the tension of continuous glass fiberstrand is disclosed. The apparatus is composed of a traveling surfacerotating about an axis. The surface has a plurality of tracks ofvariable lengths running oblique to the axis of rotation of the surface.The termination point of the track on the traveling surface is also thepoint of origin of a subsequent track. thus a continuous irregular pathis defined by the tracks. The tracks are determined by a plurality ofcontact points on which the glass fiber strand engages. The surfacetravels at a slightly greater linear speed than the take-up winder thusreducing the tension of the strand on the glass fiber strand package.Additionally. the surface may be reciprocally traversed the length ofthe take-up package or alternatively the take-up package can betraversed to obtain a random wind of glass fiber strand.

12 Claims. 3 Drawing Figures 1 METHOD AND APPARATUS FOR REDUCING TENSIONAND TRAVERSING GLASS FIBER STRAND BACKGROUND OF THE INVENTION Thisinvention relates to a method and apparatus of traversing and tensionreducing continuous glass fiber strand.

Glass fibers are formed by attenuation from a plurality of molten conesof glass at the tips of orifices in a glass fiber forming bushing.

During the formation of the filaments a sizing composition is appliedthereto to provide lubricity to the filaments so they do not abradeagainst each other and break. The sizing composition usually contains abinder which binds the filaments into a strand which is subsequentlyformed. Both the binder and the lubricant are provided not only forprocessability but also for compatibility for the final use to which theglass fibers are adapted. Such uses are typically in the fields ofplastic reinforcement, rubber reinforcement, such as tire cord, andtextile applications.

After the glass fibers are sized they are gathered into strands usuallyby means of a gathering shoe which is normally a grooved graphite wheel.The strand is then passed over a traversing mechanism which contacts thestrand and directs the strand over the surface ofa forming tube.

The forming tube is mounted on a winder which is a rotating drum orcollet providing the attenuative force to the glass fiber filamentsdrawn from the bushing. The forming tube is a thin cylindrical sleeveusually constructed of cardboard which fits securely over the windercollet. As the package is wound the strand is guided by the traversingmechanism to distribute the strand across the surface of the cylindricalforming package.

After a predetermined amount of glass fiber strand has been wound on aparticular package the attenuation process is usually stopped, the woundpackage is removed and another empty forming package is placed on thewinder and the glass fiber forming process is continued.

The interruption of the forming operation at frequent intervals isnecessitated by the minimal amount of strand which can be wound on asingle forming package. After a wind depth of about one-half inch ofstrand is reached, further winding on the forming package causes theinside strands of the package to wrinkle, in a path parallel to the axisof rotation of the forming package, due to strand tension. Thiswrinkling causes difficulty in unwinding of the packages due to breakageand difficulty in end finding.

During the formation of fibers into strand and the winding of the strandon the forming package, the attenuative force being supplied by thewinder produces substantial tension within the strand package. Thisincreased tension causes the strand to flatten when wound on thepackage. Flattening of strand detracts from the weaving characteristicsof the strand when it is used in the corresponding product area, inaddition to the wrinkling problem hereinbefore discussed.

During the winding of the strand on the forming package, the traversingmechanism causes the strand to be laid on the package at angles obliqueto the axis of rotation of the cylindrical winder. Ideally, each layerof strand on the package should be laid non-parallel to the layer ofstrand on which it is wound. however, do to a failure of the traversingmechanism to provide such non-parallelism, several parallel winds areencountered within the strand package. These parallel winds causedifficulty, in that breaking and fuzzing of the strand during subsequentprocessing occurs because fibers which are wound in parallel layers havea tendency to adhere to each other.

Therefore, the glass fiber strand industry has desired a method ofproducing and an apparatus to produce a glass fiber strand package whichis randomly wound with a minimum of parallel winds and producing astrand package with low tension.

The instant invention provides an apparatus for reducing the tension ofglass fiber strand wound on forming packages.

Additionally, the invention provides a method of winding strand on aforming package with the layers being in substantially non-parallelrelationship to each other.

Further, the invention provides an apparatus for traversing strand toform a substantially non-parallel wound forming package.

Still further, the invention provides an apparatus for reducing thetension of glass fiber forming packages. thus permitting a packagecapable of supporting a large amount of glass fiber strand.

These and other advantages of the invention will become apparent fromthe ensuing description.

BRIEF DESCRIPTION OF THE INVENTION Briefly the invention involves atraveling surface for glass strand which is positioned between thegathering shoe and the winder, in a glass fiber strand formingoperation. This traveling surface imposes a linear velocity to thestrand slightly greater than that imposed by the winder thus reducingthe tension in the strand being wound. This traveling surface iscomposed of a plurality of contact points on which the strand engages.These contact points define a plurality of tracks of travel on which thestrand rides. Each track traverses the surface of the traveling surfaceat an angle oblique to the axis of rotation of the surface. There areseveral tracks of varying length on this traveling surface. The originof any one of these tracks is the termination point of another one ofthe tracks on the traveling surface on which the strand rides. Thetraveling surface is positioned in such a manner that it contacts thestrand but does not wind the strand thereon.

Further details and other advantages of the invention will appear fromthe following description of the preferred embodiment of the inventionand the accompanying drawings in which:

FIG. 1 is a side elevational view, partly in perspective, of suitableapparatus for providing a traveling surface which reduces tension andrandomly winds glass fiber packages;

FIG. 2 is a front elevational view, partially in perspective, of theapparatus of FIG. I in operation; and

FIG. 3 is a graphic representation comparing the traversing mechanism ofthe prior art with two embodiments of the invention.

Referring now to FIG. 1, there is shown a traveling surface I mountedbetween two annular plates 2 and 3. The annular plates 2 and 3 areconstructed of a preferably light weight metal or alloy of such a metal.Aluminum and magnesium are typical metals employed and provide minimumweight on the shaft (not shown) on which the apparatus is mounted.Between the two annular plates 2 and 3 are mounted a plurality of wiremembers 4. These wire members 4 are constructed of metal such as brassor steel. These materials have substantial rigidity and consequentlyprovide constant form to the tracks 5. The wire members 4 are mounted ina plurality of apertures 6 in the annular plates 2 and 3. The tracks aredetermined by the progressive bends 7 in the wire members 4. The tracks5 are preferably of different lengths to provide a random path to thestrand to be engaged therewith. Hence, the arc length and y which defineseparate track lengths are diverse in distance. On this particularapparatus, there are four separate tracks 5, two of which are not shown.

The wire members 4 provide the point contact for the strand facing alongthe traveling surface. Point contact is preferable to minimize contactof the surface with the strand. A continuous surface which contacts thestrand is undesirable in the apparatus of FIG. 1 because the formingstrands, typically containing an aqueous sizing composition thereon,tend to adhere to a continuous surface thus causing wrapping of thestrand about a continuous surface. Any wrapping of strand on such asurface prevents adequate transfer of the strands from the surface tothe forming package on which the strands are wound. This wrapping ofstrand occurs primarily when any slight speed change of the strand isencountered by a continuous surface. Utilizing point contact on thetraversing surface in lieu of a continuous contact alleviated thiscondition.

The two annular plates, 2 and 3, are fastened together by means ofscrews 8 which are fitted into apertures 9 in the annular plate 3. Thescrews 8 are attached to sleeves 10, which are permanently affixed toannular plate 1. Thus, if wire members 4 are to be replaced or adjustedto form different track lengths, annular plates 2 and 3 can be separatedby disengaging the screws 8 and replacing the wire members 4 in theapertures 6 of the annular plates 2 and 3. Perforations 11 are providedin annular plates 2 and 3 to reduce the weight of the total apparatus ofFIG. 1. At the center of annular plates 2 and 3 is a channel 12 having asleeve member 13 mounted therein to receive a drive shaft not shown inFIG. 1. The sleeve member 13 has a key receiver 14 for securing theapparatus of FIG. 1 on the drive shaft (not shown).

Instead of the wire track configuration of FIG. 1, a continuous solidsurface can be made to produce a plurality of points on the continuoussurface to contact the strand. This can be accomplished by having,instead of wires raised portions on the continuous surface definingtracks having the mechanical characteristics of the tracks shown in FIG.1.

Other apparatus which would provide point Contact with the strand anddefine tracks through which the strand rides can be constructed by thoseskilled in the art.

Referring to FIG. 2, the apparatus of FIG. 1 is shown tension reducingand traversing a glass fiber strand 15 while the strand 15 is beingwound on a mandrel 16. The glass fiber strand 15 is formed by agathering shoe not shown which gathers the filaments produced from aglass fiber forming bushing into the strand 15. The traverse A of FIG. 1is mounted on a shaft 18 secured by a key 19 which provides the fixedattachment of the traverse A to the shaft 18. The shaft 18 is driven bya motor, not shown. The linear velocity of the surface 1 of the traverseA is greater than the linear velocity of the surface of the mandrel 16.In this particular example the linear velocity of the surface 1 is12,100 feet per minute whereas the linear velocity of the mandrel 16 is12,000 feet per minute. The normal range of speed differential betweenthe traverse A and the mandrel 16 is normally between 5 and 10 percent.Thus, the traverse A travels at a surface linear speed 5 to 10 percentgreater than the surface lil'iear speed of the mandrel 16. In general,the greater the differential maintained between the surface velocity oftraverse A and the surface velocity of the mandrel 16, the greater thedegree of tension reduction of the strand being wound. However, iftraverse A is operated at a surface linear velocity substantiallygreater than mandrel 16, the forming package formed on the mandrel 16will be too loosely wound and will cause problems in further handling ofsuch strand packages. Thus, the differential in linear speeds issomewhat dependent upon the type of forming package desired.

The strand 15, as can be seen in FIG. 2, is passed over the guide 25 ofthe free wheeling idling arm 21. The free wheeling idling arm 21 issupported by a bracket 24 which supports the mounting shaft 23. Both theguide 25 and the idling arm 21 and its support members 23 and 24 areconnected to a support arm 22 which is mounted on the shaft 18. Thus,the guide eye 25 and the idler 21 direct the strand onto the center lineof the traverse A providing a uniform plane of initial contact of thestrand 15 on the surface 1 of the traverse A.

The traverse A is traversed the length of the mandrel 16 by means ofextending and retracting the shaft 18 by a reciprocating mechanism, notshown, in the housing 20. The mandrel 16 is rotated at a constant speedby means of a driving belt 26 driven by a pulley 27. The belt 26contacts a second pulley 28 which is free wheeling about the shaft 29.As the belt 26 is turned by the pulley 27, mounted on the drive shaft30, it rotates the shaft of the mandrel 16 by means of the pulley (notshown) positioned behind the stop plate 32. As the strand 15 isaccumulated on the mandrel 16, the speed of the mandrel is adjusted sothat a constant peripheral speed is obtained on the surface of thestrand 15 wound on the mandrel 16. This adjustment in winding isachieved by programing the speed of the motor not shown to adjust thedepth of strand l5 wound on the mandrel 16. On the surface of themandrel 16 is a sleeve 31 on which the strand accumulates.

Because the traveling surface 1 of the traverse A has random tracklengths, the angle of winding of the strand 15 on the mandrel 16 withrelation to the axis of rotation of the mandrel 16 will be random,therefore producing a minimum amount of parallel winds on the strandpackage to be subsequently formed. The sleeve 31 is mounted on the shaft16 between two stop plates 32 and 33. Stop plate 32 is permanentlyaffixed to the mandrel l6 and the opposing stop plate 33 is removablymounted on the mandrel 16 to facilitate the removal of a full glassfiber forming package composed of the wound strand 15 on the sleeve 31.

After the sleeve 31 has the desired amount of glass fiber strand l5wound thereon, the hub member 34 is rotated so that another mandrel 35is in position to receive the glass fiber strand 15. The depth of windon the sleeve 31 is normally I to 2 inches as opposed to aconventionally wound package of one-half inch. This increased depth ofwind is attributable to the substantially reduced tension of the strandbecause of the tension reduction of the traverse A.

A second mandrel 35 has a sleeve 36 mounted by means of stop plates 37and 38. Stop plate37 is permanently affixed to mandrel 35."Stop plate 38is removably mounted on the mandrel 35 to facilitate the removal of afull forming package on the sleeve 36.

The means for drivingthe mandrel 35 when in position is the pulley 27affixed to the shaft 30 which is driven by a motor, not shown. The belt26 rotates the mandrel 35 by a drive pulley (not shown) positionedbehind the stop plate 37.

eration can be provided by the apparatus of the invention withoutdiscontinuance of the forming operation simply by alternating themandrel l6 and 35 and removing the full forming packages which werewound thereon.

Unlike the conventional manner of forming glass fibers, the sleeves 36and 31, with the glass fiber strand wound thereon are easily removablefrom the mandrels 35 and 16 because of the substantially reduced tensionattributed to the traverse A. Additionally, when the mandrels l6 and 35are interchanged, any change in speed of winding can be toleratedbecause the tension reducing characteristics of the traverse A preventswrapping of the strand about the traverse and looping of the strandabout either of the mandrels l6 and 35.

Further, unwinding of this strand is facilitated in that there isreduced tension in the glass fiber forming package and there is anegligible amount of parallel winds which provides for improved endfinding and a minimal amount of breaks during the unwinding of thestrand package.

The glass fiber strand produced by the apparatus of FIG. 2 issubstantially round rather than flattened due to the reduction oftension while winding on the mandrels 35 and 36 thus providing animproved glass fiber strand for the production of yarn and textile glassfi' bers,

Referring now to FIG. 3, a comparison of the transversing mechanism ofthe invention and that of the prior art is shown. in the prior art, thecommon method of traversing strand material has been by a one-cycletwo-stroke cam traverse such as is shown in US. Pat. No. 2,391,870, thestrokes being of the same length. Because of this one-cycle two-strokecam, minimal randomness is encountered causing a plurality of parallelwinds on a single strand package which in turn causes difficulty inunwinding such forming packages for subsequent use.

Graph T shows traverse which is a two cycle four variable stroke camwhich is made in accordance with the invention. The circumference ofthis cam is 45 inches and provides four different track lengths orstrokes. Each track or stroke runs directionally from one side of therotating surface to the opposite side of the rotating surface e.g.,between the two annular plates as depicted in FIGS. 1 and 2 thus, atwo-cycle cam is defined. This variable track or stroke causes therandom wind on the glass fiber forming package.

Graph U of FIG. 3 shows a traverse defined by a cam having three cyclesand six variable strokes. Again the circumference of the apparatus is 45inches and the stroke lengths vary between 5 inches and 10 inchesproviding even more random placement of the strand i the rotationalspeed of the traverse of the invention can be substantially reduced withrelation to that of the prior art since the larger circumferentialdistance, the less rotations per minute is required to achieve thedesired linear speed for tension reducing the strand. This isadvantageous in that the strain on the moving parts such as bearings andgears of the apparatus is substantially reduced.

It is apparent that within the scope of the invention modifications anddifferent arrangements may be made other than as herein described. Thepresent disclosure is illustrative of the invention comprehending allvariations thereof. The invention is not to be limited only as is setforth in the accompanying claims.

I claim:

1. A glass strand traversing apparatus for depositing a strand on aforming package comprising:

a pair of plate members,

a plurality of spaced transversely extending supporting members securedto the opposing faces of said plates, said supporting members eachhaving an inwardly depressed portion which lie upon and define anonuniform undulating path between said supporting members to provide arotatable support for said strand.

2. The apparatus of claim 1 wherein said supporting members are wiremembers.

3. The apparatus of claim 1 wherein said plate members are annular.

4. The apparatus of claim 3 wherein said supporting members are aplurality of wires mounted parallel to the axis of rotation of saidannular plate members, said wires being supported by apertures in saidannular plate.

5. In the method of forming a continuous glass fiber strand comprisingdrawing fine glass fibers from molten cones of glass at a bushing byattenuation, applying to said fibers during formation an aqueous sizingcomposition, gathering said fibers into strands, traversing the strandsacross a reciprocating path, winding said glass fiber strands on awinder, the improvement comprising pulling said strands with a pluralityof spaced transversely extending supporting members secured to theopposing faces of a pair of annular plate members, said supportingmembers each having an inwardly depressed portion which lie upon anddefine a nonuniform undulating path between said supporting members,said pulling step being interposed between said gathering step and saidwinding step.

6. The method of claim 5 including traversing said strand across thesurface of said winder during said pulling step.

7. In the method of forming continuous glass fiber strand comprisingdrawing fine fibers from molten cones of glass at a bushing byattenuation, applying to said fibers during formation an aqueous sizingcomposition, gathering said fibers into strand and collecting saidfibers, the improvement comprising applying a plu- 7 8 rality of pullingforces simultaneously at discrete points applying simultaneously, aplurality of pulling forces along said strand while imparting anundulating path of to said strand at discrete points along said strand,travel to said strands, said plurality of pulling forces applying a lastpumng force to Said Strand, subsel applied between Said gathering Stepand Said quent to said plurality of pulling forces and collectlectmgstep ing said strand.

8. The method of claim 7 wherein said collecting step is accomplished bywinding.

9. A method of forming glass fiber strand comprising: i attenuatingglass fiber filaments from molten cones T method of l 9 wberem lastpunmg of glass I 10 force 18 greater than said plurality of pullingforces. applying an aqueous sizing composition to said fila- The methodof Claim 9 wherein Said last Pulling ments, force is less than saidplurality of pulling forces. a

gathering said filaments into strand.

10. The method of claim 9 wherein said last pulling force is a winder.

1. A glass strand traversing apparatus for depositing a strand on aforming package comprising: a pair of plate members, a plurality ofspaced transversely extending supporting members secured to the opposingfaces of said plates, said supporting members each having an inwardlydepressed portion which lie upon and define a nonuniform undulating pathbetween said supporting members to provide a rotatable support for saidstrand.
 2. The apparatus of claim 1 wherein said supporting members arewire members.
 3. The apparatus of claim 1 wherein said plate members areannular.
 4. The apparatus of claim 3 wherein said supporting members area plurality of wires mounted parallel to the axis of rotation of saidannular plate members, said wires being supported by apertures in saidannular plate.
 5. In the method of forming a continuous glass fiberstrand comprising drawing fine glass fibers from molten cones of glassat a bushing by attenuation, applying to said fibers during formation anaqueous sizing composition, gathering said fibers into strands,traversing the strands across a reciprocating path, winding said glassfiber strands on a winder, the improvement comprising pulling saidstrands with a plurality of spaced transversely extending supportingmembers secured to the opposing faces of a pair of annular platemembers, said supporting members each having an inwardly depressedportion which lie upon and define a nonuniform undulating path betweensaid supporting members, said pulling step being interposed between saidgathering step and said winding step.
 6. The method of claim 5 includingtraversing said strand across the surface of said winder during saidpulling step.
 7. In the method of forming continuous glass fiber strandcomprising drawing fine fibers from molten cones of glass at a bushingby attenuation, applying to said fibers during formation an aqueoussizing composition, gathering said fibers into strand and collectingsaid fibers, the improvement comprising applying a plurality of pullingforces simultaneously at discrete points along said strand whileimparting an undulating path of travel to said strands, said pluralityof pulling forces being applied between said gathering step and saidcollecting step.
 8. The method of claim 7 wherein said collecting stepis accomplished by winding.
 9. A method of forming glass fiber strandcomprising: attenuating glass fiber filaments from molten cones ofglass, applying an aqueous sizing composition to said filaments,gathering said filaments into strand, applying simultaneously, aplurality of pulling forces to said strand at discrete points along saidstrand, applying a last pulling force to said strand, subsequent to saidplurality of pulling forces and collecting said strand.
 10. The methodof claim 9 wherein said last pulling force is a winder.
 11. The methodof claim 9 wherein said last pulling force is greater than saidplurality of pulling forces.
 12. The method of claim 9 wherein said lastpulling force is less than said plurality of pulling forces.